package com.ag777.util.lang;

/**
 * 有关 <code>emoji表情</code> 工具类。
 * <p>
 * 代码来自http://blog.csdn.net/et198901/article/details/49906797
 * </p>
 * 
 * @author 
 * @version create on 2017年10月29日,last modify at 2017年10月29日
 */
public class EmojiUtils {

	private EmojiUtils() {}
	
	/**
     * 检测是否有emoji字符
     * @param source 需要判断的字符串
     * @return 一旦含有就抛出
     */
    public static boolean containsEmoji(String source) {
    	if(source == null) {
    		return false;
    	}
        int len = source.length();
        for (int i = 0; i < len; i++) {
            char codePoint = source.charAt(i);
            if (!notisEmojiCharacter(codePoint)) {
            //判断确认有表情字符
            return true;
            }
        }
        return false;
    }


    /**
     * 非emoji表情字符判断
     * @param codePoint codePoint
     * @return
     */
    private static boolean notisEmojiCharacter(char codePoint) {
        return (codePoint == 0x0) || 
                (codePoint == 0x9) ||                            
                (codePoint == 0xA) ||
                (codePoint == 0xD) ||
                ((codePoint >= 0x20) && (codePoint <= 0xD7FF)) ||
                ((codePoint >= 0xE000) && (codePoint <= 0xFFFD)) ||
                ((codePoint >= 0x10000) && (codePoint <= 0x10FFFF));
    }
    
    /**
     * 过滤emoji 或者 其他非文字类型的字符
     * @param source  需要过滤的字符串
     * @return
     */
    public static String clearEmoji(String source) {
        if (!containsEmoji(source)) {
            return source;//如果不包含，直接返回
        }
        
        StringBuilder buf = null;//该buf保存非emoji的字符
        int len = source.length();
        for (int i = 0; i < len; i++) {
            char codePoint = source.charAt(i);
            if (notisEmojiCharacter(codePoint)) {
                if (buf == null) {
                    buf = new StringBuilder(source.length());
                }
                buf.append(codePoint);
            } 
        }
        
        if (buf == null) {         
            return "";//如果没有找到非emoji的字符，则返回无内容的字符串
        } else {
            if (buf.length() == len) {
                buf = null;
                return source;
            } else {
                return buf.toString();
            }
        }
    }
}